Drilling-machine



UNITED STATES PATENT OEEIcE.

IVILLIAM I. DALIIETT, OF FIHLADELPHIA, ASSIGNORv TO I-IIMSELF, ANDTHOMAS H. DALLETT AND GEORGE A. DALLETT, BOTH OF THORN- BURY,PENNSYLVANIA.

DRILLING-MACHIN.

SPECIFICATION forming part of Letters Patent No. 397,701, dated February12, 1889. Application tiled November l2, 1888. Serial No. 290,606. (Nomodel.)

To all whom, t may concern.-

Be it known that I, WILLIAM P. DALLETT, a citizen of the United States,and a resident of Philadelphia, Pennsylvania, have invented certainImprovements in DrillingMac-hines, ot` which the following is aspecification.

My invention relates to improvements in stationary drill-presses, moreespecially used for small work.

One object ot my invention is to overcome in a simple manner theobjection to the dropping of the drill-spindle, due to lost motion,between the iiXed pinion and the rack of the spindle, and a furtherObjectis to provide means for automatically taking up the slack ot' thedriving'belt, as fully described hereinafter.

In the accompanying drawings, Figure lis a side view of my improveddrill-press. Fig. 2 is an enlarged view showing the counterbalancing andfeeding devices for the drillspindle. Fig. 3 is a section on the line l2, Fig. 2; and Fig. 4 is a view of a moditied form of belt-driving gear.

A is the base of the drilhpress.

B is a vertical standard, on which are mounted the spindle and itsfeeding' mechanism, supported in the present instance by a bracket, D,which is held in position by a clamp-nutin the usual manner. Thisbracket, I prefer to counterbalance, as shown by dotted lines in Fig. l,in order to prevent said bracket from :falling when the securing-nut isremoved. ('larried by the standard B is a bracket, E, having three arms,e e e2. The arm e acts as a guide for the upper portion of thedrill-spindle F. The arms e e2 carry studs on which are belt-wheels a d.On the drill-spindle F is a cone-pulley, G. This pulley is splined tothe spindle, so that the spin dle will be turned bythe said pulley, butcan have an independent vertical. movement.

On the drill-spindle is a sleeve, f, having teeth l), which engage withthe teeth of the feed-pinion I, Inounted in bearings in the brackets D.Direct-ly below this pinion is a second pinion, J, also having itsbearings in This pinion also engages with One end of a spring,

the bracket D. the teeth of the rack l).

j, Fig. 3, is secured to the pinion, and the opposite end is secured tothe bracket. This spring tends to counterbalance the spindle, andconsequently keeps the upper portion of the teeth of the pinion againstthe lower portion of the-teeth ot' the rack, so that if the handle 1f ofthe feed-pinion I is moved in the direction of its arrow, Fig. 2, thelower faces of the teeth of the pinionI will bear upon the upper facesofthe teeth of the rack b. It will be seen that the rack is heldsecurely without any lost motion between the teeth of the pinion I andthe teeth of the connterbalancingpinion J.

In ordinary drilling-Inachines the weight of the spindle would besufficient to cause the drill to drop a certain distance, depending uponthe distance between the lfeed-tooth and the tooth of the rack, andconsequently tho drill would cut in to the metal to a dept-h sut iicientto snap the drill. I overcome this objection by providing the extrapinion held against the under side of the teeth of the rack by a springof sufficient strength to counterbalance the weight of the spindle, as,owing to the counterbalancing of the spindle, the drill will not biteinto the metal without pressure being applied to the spindle through themedium of the hand-lever I.

In place of the spring (shown in Fig. i) a weight may he employed whichwould answer substantially the same purpose, although not quite soconvenient.

The driving-belt for the drillis,in the pres ent instance, a round belt,m, which passes over the driving-pulley M on a driving-shaft, N, andunder a guiding-pulley, d, around the cone-pulley G, over the pulley a,to a pulley, n, on a tension-weight, 7s, and up to the pulley M.

By constructing the driving mechanism of the stationary drill in thismanner the steady driving of the drill-spindle is insured. As thetension-weight 7c keeps the belt always under a certain degree oftension, said belt does not have to be taken up at intervals, and thespeed of the drill can be changed immed ately on placing saiddriving-belt around any one of the pulleys on the cone G, and,

lurther, the drill need not be set direetly iu l line *with the shaft,or in a certain position in respect to the shaft, as vthe tehsioivweightk will always aeeonnnodate itsellt' to the .inaehine and thedriving-pulley.

In Fig. 4L I have shown the driving-pulley M on the standard A. Thedriving-belt in this instance passes np over a pulley, a, around the@one G and over a pulley, a', and then around the pulley n on the'frieti'0nweight lo, up over a supplementary belt-wheel, l, and fromthere around the driVing-pulley M. Either one of these Vforms may beused, as circumstances require.

Having thus described my invention, I el aim and desire to seeure byLetters Patent l. The Combination7 vin a drilling-madrine, 0E thedrill-spindle, a rack thereon, and two independent pinions, bothengaging with said raak, one pinion adapted to be moved by hand to fortethe drill to its work and the other pinion aeted on by a springl orweight to eounterbalane said spindle, substantially as and for thepurpose speeiiimll 2, The eo'mbinatimnin a drilling-1naehine, of theeone-pulley splin ed directly to the spind le with a belt adalited topass around `guiding'pulleys and around a pulley on' a snspendedrietion-weight and over a stationary driving-pulley, substantial] y asdescribed.

In testimony whereof I have si gn ed my naine to this specification inthe presence of two subscribing witnesses.

WILLIAM P. DALLETT.

bvitnesses:

HENRY Howson, HARRY SMITH.

